With Objective-Chipmunk, [[ChipmunkSpace alloc] init] will return a ChipmunkHastySpace if the hasty space class is linked in your executable. The NEON solver really has no downsides like the threaded one does. If you want to disable that functionality, you either need to edit the [ChipmunkSpace -init] method or remove ChipmunkHastySpace.m from the library target. Either case is going to require a recompile of Chipmunk Pro. It's also possible to do it with linker flags probably... but that sounds more complicated than it's worth.

Using the regular C API, you have to explicitly create a cpSpace or a cpHastySpace.

Oh. The trial does not come with the source code. The Chipmunk Indie package doesn't have the NEON optimizations, but does have the Objective-Chipmunk binding. You could compare the performance of those two.

I recompiled the whole thing and moved the libChipmunkPro-Iphone.a into the iphone demo project, cleaned and recompiled. Running on an Ipad, I expected to see a deterioration in the smoothness or the demos or something, but regardless of the settings, Time Scale or Time Step or even changing some of the values in the demos such as the tick value in the grabberDemo.m, I don't see any difference in the visual performance between, what I think I have in NEON mode and non-NEON mode. Am I missing something?

There is a benchmark target in the Chipmunk Pro project. That's where the numbers on the Chipmunk Pro site came from. The Chipmunk Showcase app on the other hand isn't really meant to be a benchmark, although it is supposed to saturate the CPU as much as possible on most devices. Did you also change the showcase source to use a regular Chipmunk space? It explicitly creates a ChipmunkHastySpace to enable multiple threads. Check ShowcaseDemo.m in the init method.

At least on my iPad 2, there is a *huge* difference in performance on the Pyramid Topple/Pyramid Stack demos if you force NEON/threading off. The framerate drops to the point where the UI become unresponsive and you can barely interact with it.

On an iPad 2, it's the difference between 12 and 60fps on the Pyramid demos. Not to say that it makes the physics alone 4x faster, but it frees up a lot time for rendering and the user interface code to run.

Thanks for all your help so far. I have made the changes you suggested, and was really hoping for a dramatic visual demonstration of NEON against non-NEON. Both modes appear visually the same even on all of the demos. The performance display I get matches your statistics, 14 FPS on the non-NEON and 60 FPS on the NEON. Any ideas on how I would demonstrate that visually other than the performance numbers.